Abstract: A spiral blade unit is disclosed, which generates less blade-sagging, deformation, or vibration, can be made of various material, can be made with light material, and can be installed easily in interconnecting spiral blades. The spiral blade unit includes a rotational axle and spiral blades with root portions attached along an outer circumferential surface of the rotational axle, and the spiral blades are interconnected to one another through a blade connector.

Abstract: Disclosed is a friction damper that has a unique load-displacement hysteresis characteristic such that, when the frictional coefficient between members that generate friction is smaller than the slope of an inclined surface, the friction damper is always returned to the original position thereof in a case where an external force is removed or remains at a level that does not exceed a threshold value. The V-groove friction damper includes: a V-groove member including a concave V-shaped groove; a V-shaped frictional contact member including a V-shaped frictional contact portion; a guide member configured to guide a left/right movement of the V-groove member; and an elastic compression unit installed on the guide member, and configured to elastically compress the V-shaped frictional contact member toward the V-groove member.

Abstract: Disclosed is a friction damper that has a unique load-displacement hysteresis characteristic such that, when the frictional coefficient between members that generate friction is smaller than the slope of an inclined surface, the friction damper is always returned to the original position thereof in a case where an external force is removed or remains at a level that does not exceed a threshold value. The V-groove friction damper includes: a V-groove member including a concave V-shaped groove; a V-shaped frictional contact member including a V-shaped frictional contact portion; a guide member configured to guide a left/right movement of the V-groove member; and an elastic compression unit installed on the guide member, and configured to elastically compress the V-shaped frictional contact member toward the V-groove member.

Abstract: A spiral blade unit is disclosed, which generates less blade-sagging, deformation, or vibration, can be made of various material, can be made with light material, and can be installed easily in interconnecting spiral blades. The spiral blade unit includes a rotational axle and spiral blades with root portions attached along an outer circumferential surface of the rotational axle, and the spiral blades are interconnected to one another through a blade connector.

Abstract: A seismic isolator is provided, which is excellent in vertical shock-absorbing and vibration reducing, has more functions of horizontal shock-absorbing, recovering, and reaction-force resisting, is easy to install while adjusting the horizontal level of supporting structure in the construction site, and is able to adjust the height of the supporting structure even after installed in the construction site. The seismic isolator includes a wedge unit including a rod, a pair of wedges installed movably along the rod, a horizontal elastic body engaging the rod and supporting the pair of wedges and a supporting means supporting the horizontal elastic body, a wedge bottom surface member supporting the pair of wedges while surface-contacting a wedge bottom surface of the wedge surface of the pair of wedges, and a wedge top surface member supported by the pair of wedges while surface-contacting a wedge top surface of the wedge surface of the pair of wedges.

Abstract: A seismic isolator is provided, which is excellent in vertical shock-absorbing and vibration reducing, has more functions of horizontal shock-absorbing, recovering, and reaction-force resisting, is easy to install while adjusting the horizontal level of supporting structure in the construction site, and is able to adjust the height of the supporting structure even after installed in the construction site. The seismic isolator includes a wedge unit including a rod, a pair of wedges installed movably along the rod, a horizontal elastic body engaging the rod and supporting the pair of wedges and a supporting means supporting the horizontal elastic body, a wedge bottom surface member supporting the pair of wedges while surface-contacting a wedge bottom surface of the wedge surface of the pair of wedges, and a wedge top surface member supported by the pair of wedges while surface-contacting a wedge top surface of the wedge surface of the pair of wedges.